Reservoir Evaluation and Development ›› 2022, Vol. 12 ›› Issue (1): 139-149.doi: 10.13809/j.cnki.cn32-1825/te.2022.01.012

• Shale Gas • Previous Articles     Next Articles

Geological characteristics of mud shale in Da'anzhai section of Fulu Town, Liangping

ZHU Tong1,2,3(),ZHANG Zhe4,FENG Dongjun1,2,3,ZHENG Rongcai5,WANG Feng6,PENG Yongmin1,2,3   

  1. 1. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China
    2. Sinopec Key Laboratory of Shale Oil/Gas Exploration and Production Technology, Beijing 100083, China
    3. Sinopec Petroleum Exploration and Production Research Institute, Beijing 100083, China
    4. China University of Geosciences, Beijing 100083, China
    5. Chengdu University of Technology, Chengdu, Sichuan 610059, China
    6. Sinopec Oilfield Exploration and Development Department, Beijing 100029, China
  • Received:2021-11-08 Online:2022-02-26 Published:2022-03-24

Abstract:

The lacustrine mud shale in Jurassic of Sichuan Basin is characterized by fast sedimentary phase transition, complex and diverse lithological combination types, and strong reservoir inhomogeneity, which is quite different from the marine shale. Therefore, it is of great significance to establish a typical geological section of Jurassic lacustrine shale in Sichuan Basin and further study the microfacies and lithologic assemblage characteristics of lacustrine shale. The Da'anzhai section of Fulu Town, Liangping District, Chongqing, Eastern Sichuan is selected as the research object. Through the division of small layers, fine description of sedimentary microfacies and lithologic combination characteristics, sample collection, field profile measurement, organic geochemistry, reservoir physical properties and whole rock X-ray diffraction, it is shown that the Da'anzhai section of Fulu town is mainly carbonate lake sediments. The microfacies and lithologic assemblages have three stages: initial transgression, maximum transgression and initial regression. The first and third members of the Da'anzhai formation are mainly composed of the microfacies of the thick layer mesoclastic limestone deposited in the bioclastic beaches of the carbonate shallow lake; The second member of Da'anzhai formation is a semi deep lacustrine subfacies. There are two microfacies: Storm beach and semi deep lacustrine mud. They are characterized by two lithologic associations, i.e. unequal thickness interbedding of grey clastic limestone and grey black shale, and thick black shale with thin shell limestone, With high content of brittle minerals and better permeability and compressibility, it is a sweet spot for shale oil and gas enrichment. Compared with the typical shale gas drilling, The semi deep lacustrine facies of the second member is mainly distributed in Fuling Jiannan area in eastern Sichuan, which is conducive to the formation of shale oil and gas. The carbonate shallow lacustrine clastic shoals of the first and third members are mainly distributed in Central Sichuan Northeast Sichuan, which is conducive to the enrichment of tight oil and gas.

Key words: lithological association, continental shale, shale oil and gas, Da'anzhai section, Fulu Town section, Sichuan Basin

CLC Number: 

  • TE122